Effect of mica content on pore pressure and stress-strain response of micaceous sand using energy dissipation and different failure mechanisms

Mica particles are platy, flexible and resilient in nature having numerous intact mica flakes foliated over each other with low stiffness. Presence of mica among sand particles creates complex geometric arrangements due to bridging, ordering or pore filling phenomena; which make micaceous sand highly compressible with low shear strength. When flaky mica particles are augmented among spherical sand particles, the governing shear behaviour mechanisms substantially varies due to redistribution of contact forces among sand-sand matrix, sand-mica matrix and mica-mica matrix formation of micaceous sand. The current experimental study investigated the effect of mica content on pore pressure and stress-strain behaviour of micaceous sand due to varying sand-mica microstructural evolutions. The variation in shear strength parameters were studied under different failure criteria: peak deviatoric stress and peak effective stress ratio. The deviations in mechanical behaviour of micaceous sand at varying mica content were further examined through cumulative dissipated strain energy mechanisms to understand the inter-particle contact-force transfer mechanisms for varying sand and mica matrix.